As the sophistication of reactive force fields for molecular modeling
continues to increase, their use and applicability has also expanded,
sometimes beyond the scope of their original development. Reax Force
Field (ReaxFF), for example, was originally developed to model chemical
reactions, but is a promising candidate for modeling fracture because of
its ability to treat covalent bond cleavage. Performing reliable
simulations of a complex process like fracture, however, requires an
understanding of the effects that various modeling parameters have on
the behavior of the system. This work assesses the effects of time step
size, thermostat algorithm and coupling coefficient, and strain rate on
the fracture behavior of three carbon-based materials: graphene,
diamond, and a carbon nanotube. It is determined that the simulated
stress-strain behavior is relatively independent of the thermostat
algorithm, so long as coupling coefficients are kept above a certain
threshold. Likewise, the stress-strain response of the materials was
also independent of the strain rate, if it is kept below a maximum
strain rate. Finally, the mechanical properties of the materials
predicted by the Chenoweth C/H/O parameterization for ReaxFF are
compared with literature values. Some deficiencies in the Chenoweth
C/H/O parameterization for predicting mechanical properties of carbon
materials are observed. (c) 2015 Wiley Periodicals, Inc.